Question: $ { \left[\begin{array}{rr}{1} & {-1} \\ {3} & {1}\end{array}\right]-\left[\begin{array}{rr}{4} & {2} \\ {4} & {-1}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{4} & {-1}-{2} \\ {3}-{4} & {1}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {-3} \\ {-1} & {2}\end{array}\right]}$